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<TITLE>RE: [sdiy] Taking the USB plunge...</TITLE>
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<P><FONT SIZE=2>> At my job (if you can call that...I guess I should be greatful I</FONT>
<BR><FONT SIZE=2>> have one for the time being), my current project is involving </FONT>
<BR><FONT SIZE=2>> the use of</FONT>
<BR><FONT SIZE=2>> a USB interface...So, I ordered a EZ-USB from Cypress. This </FONT>
<BR><FONT SIZE=2>> thing seems</FONT>
<BR><FONT SIZE=2>> to fit the bill for what I need to do at work...also, it seems to fit</FONT>
<BR><FONT SIZE=2>> the bill as a substitute for a Midi interface...I might have to think</FONT>
<BR><FONT SIZE=2>> about trying to use one of these to make a USB-> CV converter...</FONT>
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<P><FONT SIZE=2>We use the EZUSB at work too. IMO, it's a better alternative to FTDI for more than one-off designs if you are constrained to a UART interface between the USB engine and your device. </FONT></P>
<P><FONT SIZE=2>Now host side the driver (required) is another kettle of fish. After climbing the learning curve on MS tools and techniques, driver design and debug is a ton of work. Cypress provides a short cut: You can obtain a USB to serial driver from them. It makes your USB look like a COM port. I'm sure someone with the right background can make it look like a MIDI port. There might even be a worthwhile commercial opportunity in that.</FONT></P>
<P><FONT SIZE=2>I can see two problems with USB as the channel for MIDI: First is the lack of ground isolation. Second is the fact that USB peripherals are essentially polled at 1ms intervals (best case). Polling has potentially big problems in a realtime interface. Dig deeper and you need to consider the possibility of data loss (bulk vs. isochronous) which is not acceptable in MIDI.</FONT></P>
<P><FONT SIZE=2>Then you gotta buy a VID from the USB cops...</FONT>
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<P><FONT SIZE=2>John Speth</FONT>
<BR><FONT SIZE=2><A HREF="mailto:johns@molectron.com">mailto:johns@molectron.com</A> </FONT>
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